1. Field of the Invention
The present invention relates to a fueling device for fueling a fuel tank through a passage of a fuel filler pipe.
2. Description of the Related Art
In conventional fueling devices for fueling a fuel tank through a filler pipe, the fuel cap is open when fuel is supplied through a fuel filler pipe. The fuel cap has a sealing member which, in a closed position, is inserted between the fuel cap and an inlet opening of the fuel filler pipe to prevent fuel vapor in the fuel tank from escaping into the atmosphere. The sealing member is in the form of a gasket extending around the periphery of a cylindrical casing main body. When the fuel cap is screwed onto the opening of the filling neck, the gasket provides air-tight sealing force, while subject to torque caused by rotating friction force, against the filling neck.
Applicant has found that such torque is not readily applied uniformly across the gasket as a whole, and complicates efforts to improve the sealing properties. Additionally, the gasket is removed with the fuel cap when the fuel cap is placed in the open position, resulting in stains and damage to the seal surface of the gasket. In such cases, not only are the sealing properties of the gasket compromised, but there is greater friction resistance with the gasket, tending to result in greater operating force required to open and close the fuel cap.
Furthermore, when a fueling gun is introduced into the inlet opening, the fueling gun strikes the inlet opening, damaging the seal in the opening in contact with the gasket. The sealing properties are compromised in this case as well due to possible damage to the gasket.